Braun tube



Feb. 18, 1941. w. UHLMANN- BRAUN TUBE Filed July 28, 1958 //7vento/Wolfram U/zlma/m b y Hitarney Patented Feb. 18, 1941 UNITED STATESPATENT OFFICE BRAUN TUBE Application July 28, 1938, Serial No. 221,676

Germany July 31, 1937 2 Claims.

The present invention relates to Braun tubes, and more specifically toimprovements in or relating to the electrode lead-in conductors whichare extended through the wall of the vacuum vessel of 5 such tubes.

It is a well known expedient in connection with conductors which are tobe fixed in the wall of a vacuum vessel in a vacuum seal fashion to usea wire which is preparatorily covered with a coating of a vitreousmaterial, such as glass, and to place this glass-covered wire in itsrelative position in an aperture of the vacuum vessel, whereupon thematerial of the vessel and the glass coating about the wire areintimately united with one another 15 in a melting process.

The invention makes use of the known glasscovered lead-in conductors,and has for its object to fix the entire number of electrode lead-inconductors in one annular portion formed in the o throat of the Brauntube, so as to avoid the necessity of providing one separate aperture inthe wall for each individual lead-in conductor. It is thus possible bymeans of the present invention to eliminate the heretofore known method25 which was suitable merely for fixing one or two lead-in conductors.

The invention will be more readily understood from the followingdescription taken in conjunction with the accompanying drawing, thesingle 30 figure of which is an exaggerated schematic cross sectionalview of one embodiment according to the invention. The vacuum vessel ofthe Braun tube embodying the invention has partially been broken out inthe drawing.

35 In the figure, I denotes the vacuum vessel of a Braun tube. Thecathode ray producing and defleeting means are indicated at 2 in a pureschematic manner for the sake of simplicity and, by the same reason,only two of a plurality of elec- 40 trade lead-in conductors 3 areshown. Each electrode of the cathode ray producing and deflecting means2 is provided with a connector 5 and all of said connectors are fixed ina plate or disc I of a ceramic substance. Each connector I is welded toits appertainlnglead-in conductor at a.

The vacuum vessel I consists of two portions, AandBofgla-ss.OneendoftheportionAis drawn down to form a throat 6, and the portion B50 has an annular extension l which is adapted to fit the throat I. Theinner surface of this throat 6 and theouter surfaceofthe annulus i areboth coated with a vitreous melt and, moreover, the appropriate portionsof the leads I are likewise 55 provided with a coating ll of glass. Theglass coatings I, S and it are fused together with one another as shownto the left in the drawing. The individual glass coatings prior to thefusing oper ation are shown to the right of the drawing. It is thusobvious that the throat i and the extension 5 1 together form an annularmember by means of which the leads 3 are fixedly mounted.

The above described arrangement may be manufactured in the followingmanner: The cathode ray producing and deflecting means 2 are 10assembled to one unit which is inserted in the portion A of the envelopeor vessel I, and the corresponding end thereof is drawn down to asuitable smaller diameter and cut so as to provide a throat 6. Thelead-in conductors l are then ll welded at a to their respectiveelectrode connectors 5, whereupon the glass-covered portions of theleads are bent toward the glass coating I of the throat S and fusedthereto. This fusing may be a provisional step which merely serves forpre liminarily obtaining a sticking between the leads I and the throati. The preparatorily tapered portion B is now brought into position withits annular extension or collar I, thus facingthe throat 6 and the leads8, whereupon theglass portion I which, as mentioned above is applied onthe outer surface of the extension I is preparatorily fused to the glasscoating ll of the leads 3. These provisional fusings between the glasscoatings 8, Ill and 9, III, respectively, are then completed to aperfect vacuum seal and at the same time the tapered end of the vesselportion B is drawn down so as to provide an evacuating-pipe II. It is onthe other hand possible to partially remove the end of the portion Bremote from the extension or collar 1 andto attach a complete evacuatingpipe to the remainder of portion B in any suitable manner.

What is claimed is:

l. A method of manufacturing Braun tubes 49 which consist of twoportions, one of which is shaped to provide a throat of annular shape,the other having an annular extension which is received by the throatportion which method comprises the following sequence of steps: cuttingthe 5 tapered end of one of the portions of said Braun tube vessel toform a throat, applying a vitreous melt to the inner surface of saidthroat, placing glass-coated lead-in conductors in their appropriatepositions relative to said throat, provision- 50 ally fusing saidconductors to said throat, placing another giass-covered portion of saidBraun tube vessel in position relative to said throat, and fusing saidglass' coatings and said vitreous melt to a vacuum seal.

10 glass-coated lead-in conductors in their appropriate positionsrelative to said throat, provisionally fusing said conductors to saidthroat. placing another glass-covered portion of said Braun tube vesselin position relative to said throat, fusing said glass coatings and saidvitreous melt with said lead-in conductors there-between to a vacuumseal and drawing down the remote end oi said attached portion of theBraun tube vessel to form an exhaust tube.

wormAM UHLMANN. 10

